Why does Boots sell homeopathy like it's real medicine?

My girlfriend went into Boots on Wednesday. She's got a bad knee, twisted it while skiing, and she'd heard that arnica was good for strains and bruises – professional athletes use it as an anti-inflammatory. So, as I said, she went to Boots and bought some arnica.

Except she didn't. She bought some sugar.

Not being a massive nerd like me, and not following various other nerds on Twitter, the word "arnica" did not immediately flag up for her the associated words "homeopathy" and "quackery", as it did for me (see the splendid 10:23 campaign for more information). I asked her if I could have a look at it. Sure enough, she had bought a homeopathic arnica solution.

Now, for those of you who don't know the theory behind homeopathy, I'll explain. It is based on the thinking of an 18th-century physician called Samuel Hahnemann. The idea is twofold: 1) like cures like and 2) dilution increases potency. The first, which seems to have be inspired by vaccination, says that something which causes your problem will cure it; so caffeine will cure sleeplessness, for instance. The second – and this is where it gets weird – means exactly what it says.

To increase the potency of their solution, homeopaths dilute it enormously. They take a drop of the active ingredient and dilute it in 100 drops of water. Then they do the same. And then again. Each of those is a 1C dilution; most solutions are 24C, or 30C, or even higher.

I'm not going to get into whether homeopathy works better than placebo here, for two reasons: 1) it doesn't and 2) it is placebo. Nor do I want to get into the whole "memory of water" nonsense (or "memory of sugar", I should say), because it has been torn apart by better writers than me.

But I am going to ask why Boots, a respected high street chemist, can sell my unsuspecting better half something labelled "arnica" when it might be more accurately labelled "no arnica"*. It's on the shelves next to the medicines, for God's sake, and the only sign that it's anything other than a real active medicine is a tiny label, in perhaps 3pt font, saying "homeopathic medicinal product without approved therapeutic indications." Translation: it does nothing, because it contains nothing. But we'll charge you a fiver for it anyway.

I'm not saying we should ban homeopathy. It's a free country and people can spend their money on whatever half-baked delusional joke-shop remedies they want** (although I draw the line at providing it on the NHS). But if Boots are going to sell it, could they not put it under a sign saying "Make-believe medicine"? Or "gullibility pills"? That way everyone's happy.

*actually, and unusually, the bottle she found was 6C, or one part in 1,000,000,000,000 arnica. So the odds are that there were a few molecules of active ingredient in it. But it is still thousands of times less than the concentration of arsenic in tapwater, and if you were sold tapwater when you were trying to poison someone, you'd probably want your money back.
**unless it's made from tiger penises, or rhino's horn, or whatever. Then you should really just stop.